Grating Coupler Structure With Embedded Reflector for Higher Coupling
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Solution Overview
Problem
The coupling efficiency of grating couplers in optical transceiver modules is a critical performance determinant in high-speed optical communication systems, and existing technologies require improvements to achieve optimal efficiency.
Innovation Solution
A semiconductor structure is fabricated with an optical reflective layer embedded in the semiconductor substrate, and grating couplers and waveguides are formed on a patterned dielectric layer covering the optical reflective layer, enhancing the coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grating couplers are formed on a dielectric layer without an optical reflective layer, then the device complexity is reduced, but the coupling efficiency deteriorates
Solution Approach 1:
The optical reflective layer is embedded within the semiconductor substrate, nesting the reflective function inside the substrate structure. This allows the grating coupler formed on the dielectric layer to utilize the embedded reflective layer, improving coupling efficiency without adding external complexity to the overall device architecture.
Solution Approach 2:
The optical reflective layer is positioned in a different spatial dimension (embedded within the substrate) rather than being placed on top of the dielectric layer with the grating coupler. This vertical integration in the depth dimension enables improved coupling efficiency while maintaining a planar surface structure for fabrication compatibility.
2Reliability
If an optical reflective layer is embedded in the semiconductor substrate, then the coupling efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The optical reflective layer is formed and embedded in the semiconductor substrate before the grating coupler is fabricated on the dielectric layer. This preliminary action allows the reflective layer to be precisely positioned and integrated into the substrate structure, establishing a stable foundation that simplifies subsequent grating coupler fabrication and reduces overall manufacturing precision requirements.
Solution Approach 2:
The dielectric layer serves as an intermediary between the embedded optical reflective layer in the substrate and the grating coupler structure. This intermediate layer provides a fabrication-friendly surface for forming the grating coupler while allowing optical interaction with the reflective layer below, decoupling the precision requirements of substrate integration from surface patterning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The integration of an optical reflective layer within the semiconductor structure significantly enhances the coupling efficiency of grating couplers, improving the performance of optical transceiver modules in high-speed communication systems.
Implementation Method 1
an optical reflective layer embedded in the semiconductor substrate
Data Source
AI summary
A semiconductor structure including a semiconductor substrate, a first patterned dielectric layer, a grating coupler and a waveguide is provided. The semiconductor substrate includes an optical reflective layer. The first patterned dielectric layer is disposed on the semiconductor substrate and covers a portion of the optical reflective layer. The grating coupler and the waveguide are disposed on the first patterned dielectric layer, wherein the grating coupler and the waveguide are located over the optical reflective layer.